feat(deprecated) Fix host function, and drop the empty vm::Ctx correctly.

lib/deprecated/runtime-core/src/instance.rs

@@ -3,6 +3,7 @@ use std::error::Error;
 
 pub use new::wasmer::Exports;
 
+#[derive(Debug)]
 pub(crate) struct PreInstance {
     pub(crate) vmctx: vm::Ctx,
 }

lib/deprecated/runtime-core/src/module.rs

@@ -3,12 +3,13 @@ use crate::{
     error::InstantiationError,
     import::{ImportObject, Namespace},
     instance::{Instance, PreInstance},
-    new,
+    new, vm,
 };
 use new::wasmer_runtime::Export;
 use std::{
     collections::HashMap,
     convert::{AsRef, Infallible},
+    ptr,
 };
 
 pub use new::wasm_common::{DataInitializer, ExportIndex};
@@ -49,8 +50,29 @@ impl Module {
                 .into_iter()
                 .map(|((namespace, name), export)| match export {
                     Export::Function(mut function) => {
-                        if function.vmctx.is_null() {
                         // That's an ugly hack. Go your way :-].
+                        {
+                            // An empty `vm::Ctx` was created in
+                            // `Func` as a host function
+                            // environment. The internals of
+                            // `new::wasmer::externals::Function`
+                            // passes the environment inside the
+                            // `VMContext` pointer. That's another
+                            // hack.  This empty `vm::Ctx` must be
+                            // replaced by another `vm::Ctx` value
+                            // owned by `Instance`, because that's the
+                            // only way to update this structure
+                            // correctly for compatibility
+                            // purposes. Before doing this operation,
+                            // we must drop the empty `vm::Ctx` first.
+                            unsafe {
+                                ptr::drop_in_place::<vm::Ctx>(function.vmctx as _);
+                            }
+
+                            // And now we can update the pointer to
+                            // `VMContext`, which is actually a
+                            // `vm::Ctx` pointer, to fallback on the
+                            // environment hack.
                             function.vmctx = pre_instance.vmctx_ptr() as _;
                         }
 

lib/deprecated/runtime-core/src/typed_func.rs

@@ -5,7 +5,6 @@ use crate::{
     types::{Type, Value},
     vm,
 };
-use std::ptr;
 
 pub struct Func {
     new_function: new::wasmer::Function,
@@ -14,19 +13,21 @@ pub struct Func {
 impl Func {
     pub fn new<F, Args, Rets>(func: F) -> Self
     where
-        F: new::wasm_common::HostFunction<Args, Rets, new::wasm_common::WithEnv, vm::Ctx>,
-        Args: new::wasm_common::WasmTypeList,
-        Rets: new::wasm_common::WasmTypeList,
+        F: new::wasmer::HostFunction<Args, Rets, new::wasmer::WithEnv, vm::Ctx>,
+        Args: new::wasmer::WasmTypeList,
+        Rets: new::wasmer::WasmTypeList,
     {
-        // Create a fake `vm::Ctx`, that is going to be overwritten by `Instance::new`.
-        let ctx: &mut vm::Ctx = unsafe { &mut *ptr::null_mut() };
+        // Create an empty `vm::Ctx`, that is going to be overwritten by `Instance::new`.
+        let ctx = vm::Ctx::new();
 
         // TODO: check this, is incorrect. We should have a global store as we have in the
         // wasmer C API.
         let store = Default::default();
 
         Self {
-            new_function: new::wasmer::Function::new_env(&store, ctx, func),
+            new_function: new::wasmer::Function::new_env::<F, Args, Rets, vm::Ctx>(
+                &store, ctx, func,
+            ),
         }
     }
 

lib/deprecated/runtime-core/src/types.rs

@@ -26,9 +26,8 @@ pub use new::wasm_common::{
     TableType as TableDescriptor,
     Type,
     ValueType,
-    WasmExternType,
 };
-pub use new::wasmer::Val as Value;
+pub use new::wasmer::{Val as Value, WasmExternType};
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct GlobalDescriptor {